Process and apparatus for treating oils



Oct. 2, 1934. c. P. DUBBS PROCESS AND APPARATUS FOR TREATING OILSOriginal File d June 22. 1921 i l/Ml Carbon P2111255.

Patented Oct. 2, 1934 UNITED STATES PATENT OFFICE Carbon P. Dubbs,Wilmette, 111., assignor to Universal Oil Products Company, Chicago,111., a

corporation of South Dakota Application June 22, 1921, Serial No.479,444

8 Claims.

This invention relates to improvements in process and apparatus fortreating oils and refers more particularly to a process in which theoil, after being cracked under pressure, is separated .5 into a liquidand vapor portion, the vapors being refluxed and condensed into pressuredistillate vwhile the liquid portion is directed at a reduced oratmospheric pressure, to a dephlegmating zone of reduced pressure andthe vapors formed due to this reduction in pressure refluxed andcondensed as a separate distillate; to provide a process in which thedistillates collected may be returned and introduced with the raw oil asa refluxing medium to either or both of the refluxing stages and aprocess in which regulated quantities of the reflux and raw oil may bereturned to the primary heating zone for treatment; to provide a processin which an increased yield is procured and distillates of a moreuniform character separated from the oil body and to provide anapparatus for carrying out this process.

The single figure is a diagrammatic side elevational view of theapparatus.

In the cracking of hydrocarbon oils as it is commonly practiced, bypressure distillation, there is a. considerable quantity of relativelyhigh boiling point cuts or fractions carried ofi with the residuum inliquid form, which could easily be relieved from the residuum and bothincrease the yield and further supply a liquid distillate which it ispossible to return to be reheated and cracked into desirable marketableproducts. In the process herein disclosed, the residuum drawn from thevaporizing chamber is directed to a refluxing zone under reducedpressure and there the vapors which separate under the reduced pressure,are refluxed and pass over to a separate condenser and receiver.

Referring in detail to the drawing, the raw oil is introduced from anyextraneous source through the inlet pipe 1 and may be charged throughthe line 2 controlled by a valve 3 and pumped by means of the pump 4 andline 5 to the top of the secondary dephlegmator 6 or directed to theline '7 regulated by a valve 8, and introduced to the heating coils 9through the pump 10 and line 11 in which is interposed a valve 12. Byclosing the valve 12, the oil may be forced through the vertical line 13regulated by a valve 14 and introduced into the primary dephlegmator 15where it serves as a cooling medium in refluxing the oil vapor. Bycontrolling valves 12 and 14 regulated quantities of raw oil may bedirected to the dephlegmator 15 and coil 9. In its travel through thedephlegmator 15, the oil will reflux out higher boiling pointcondensates and carry them with the raw oil down through the return line16 regulated by a valve 1'7 which is connected to the line 11, whichleads to the heating tubes. The heating tubes are mounted in the furnace18, preferably heated by means of gas burners 19. After being raised toa cracking temperature in the heating zone, the oil passes to avaporizing chamber 20 through the transfer line 21, controlled by athrottle valve 22. In the vaporizing chamber the oil body is convertedinto a vaporized portion which passes over through the vapor line 23' tothe dephlegmator 15 and a liquid or residual portion which is drawn offthrough the line 24 in which is interposed a valve 25. The vaporspassing through the dephlegmator 15 are refluxed by the raw oil asexplained and pass over through the line 26 to a water condenser coil27, thence to a receiver 28 in the form of pressure distillate. Thepressure on this portion of the system may be accurately regulated bymeans of the pressure relief valve 29. The liquid or residual portionfrom the vaporizing chamber 20 is conducted through the line 24 and isintroduced into the bottom of the secondary dephlegmator 6.

Itwill be noted that there is a substantial reduction of pressurebetween the vaporizing chamher and the secondary dephlegmator which isaccurately controlled by means of the valve 25. This reduction ofpressure will vary according to the distillate desired and may rangefrom any pressure slightly less than that maintained in the primarysystem down to atmospheric. The residual liquid oil on passing to thereduced pressure zone in the dephlegmator 6 releases therein vaporswhich rise in the dephlegmator and pass over through the line 30 to thewater condenser 31 and receiver 32 in the form of a separate distillate.The still liquid portion which collects in the bottom of thedephlegmator 6 is drawn off through the line 33 and may be transferredto storage through the pipe 34 controlled by a valve 35 or may bedirected by the pump 10 back through the connecting 'line 36 regulatedby a valve 37. It will be noted that the raw oil is introduced to thetops of both of the dephlegmators as a refluxing medium. The separatedistillates collect in the receiving tanks and maybe Q drawn ofl?through the valves 38 and 39 respectively or by introducing thedistillates through the valves 40 and 41 to the pump 42 they may becombined and charged through the line 43 to the top of the dephlegmatorswhere separate leads 44 and 45 controlled by valves 46 and 47respectively permit the introduction of regulated quantities of combineddistillate to the top of either or both of the dephlegmators. Theconnections are such that the distillates may be combined and pumpedback into the top of either or both of the dephlegmators or eachdistillate in turn may be separately returned and charged to thedephlegmator desired.

The particular method of operation will vary with difierent factorsinvolved, that'is, operating conditions may be such that it will bedesirable to return only the distillate procured from vapors released inthe secondary dephlegmator. In such a case the distillate from thereceiving tank 32 may be pumped back separately and the distillate fromthe receiver 28 drawn ofi through the valve 38. At another time, it maybe advantageous to the operation of the process to return the combineddistillate and introduce it into either the primary or secondarydephlegmator alone and in such case, the valves must be so manipulatedas to afiect the returning of the distillate in this manner.

It will also be noted that the pump 10 is so connected in the systemthat the liquid portion from the secondary dephlegmator when not drawnoff to storage will be charged with the raw oil to the top of theprimary dephlegmator or it may be charged directly with the raw oilthrough the line 11 to the heating tubes. Numerous variations in thedirecting of both the raw oil and pressure distillate may be effectedand the temperature control in the dephlegmating columns therebyaccurately regulated.

In treating Mid-Continent gas oil of approximately 30 to 32 Baum at atemperature from 700 to 900 degrees F., and a pressure of from 100 to500 pounds, vaporizing, refluxing and condensing the vapors released inthe vaporizing chamber and transferring the residuum to a zone ofreduced pressure and separately refluxing and condensing the Vaporsreleased therein, it is possible to produce a high grade pressuredistillate of approximately 50 to 52 degrees Baum from the primarydistillation and a distillate of some lower gravity in the seconddistillation stage varying, of course, with the reduction of pressure inthe secondary zone and other factors such as the temperature in therefluxing and condensing stages.

I claim as my invention:

1. A process for treating oil, consisting in cracking the oil under asubstantial pressure in a heating and vaporizing zone, dephlegmating,condensing and collecting the generated vapors, directing theunvaporized portion to a separate dephlegmating zone and theredistilling it at a reduced pressure, condensing and collecting thevapors produced thereby separately, and returning the distillate fromthe separate condensing zones to the dephlegmators.

2. A process for treating oil, consisting in cracking the oil under asubstantial pressure in a heating and vaporizing zone, dephlegmating andcondensing the generated vapors, passing the unvaporized portion fromthe vaporizing zone, to a separate dephlegmating and condensing zone andthere vaporizing it at a reduced pressure and collecting the distillatesproduced in the two zones of condensation and returning them separatelyto either dephlegmating zone.

3. In anapparatus for treating oil, the combination with heating andvaporizing means for cracking the oil under pressure, of dephlegmatingmeans connected with the vapor and the liquid drawoffs from thevaporizing means, separate condensing and collecting apparatus connectedto each dephlegmator, means for returning the distillate produced toboth dephlegmating means and means for maintaining a reduced pressure inthe dephlegmating and condensing means connected with the liquid drawoflfrom the vaporizing means.

4. A process of treating hydrocarbon oils, consisting in raising the oilto a cracking temperature in a heating zone under a superatmosphericpressure, in introducing the oil to an enlarged vapor chamber where asubstantial portion thereof vaporizes under a superatmospheric pressure,in passing said vapors to a dephlegmator, in passing unvaporized oilfrom said vapor chamber to a second dephlegmator while said oil is in ahighly heated condition, in substantially reducing the pressure on theoil in saiddephlegmator while it is sufliciently hot to cause avaporization of a substantial portion thereof under such reducedpressure, in separately discharging and separately condensing the vaporsfrom said dephlegmators, and in introducing the distillate obtained tosaid dephlegmators to assist in condensing the heavier oil fractions.

5. A process of treating hydrocarbon oils, consisting in raising the oilto a cracking temperature in a heating zone under a superatmosphericpressure, in introducing the oil to an enlarged vapor chamber where asubstantial portion thereof vaporizes under a superatmospheric pressure,in passing said vapors to a dephlegmator, in passing unvaporized oilfrom said vapor chamber to a second dephlegmator while said oil is in ahighly heated condition, in substantially reducing the pressure on theoil in said dephlegmator while it 119 is sufficiently hot to cause avaporization of a substantial portion thereof under such reducedpressure, in separately discharging and separately condensing the vaporsfrom said dephlegmators, in introducing the distillate obtained to saiddephlegmators to assist in condensing the heavier oil fractions, and inthen returning unvaporized distillate with reflux condensate to thecracking zone for retreatment.

6. A continuous process of cracking oil comprising circulating oil in aclosed cycle circuit, cracking the oil by distillation under a highpressure and temperature in one portion of the circuit,' distilling the'residual oil from said cracking by evaporating it under a reducedpressure in another portion of the circuit, and separately collectingcondensate from the distillations in the difierent portions of thecircuit.

7. A continuous process of cracking oil comprising circulating oil in aclosed cycle circuit, cracking the oil by distillation under a highpressure and temperature in one portion of the circuit, evaporating theresidual oil from said cracking by distillation under a reduced pressurein another portion of the circuit, separately collecting condensatesobtained from the distillations in the different portions of thecircuit, introducing oil into the cracking portion of the circuit, andapplying heat only to the oil being introduced into the cracking portionof the circuit.

8. An oil distilling apparatus comprising a pipe still, a crackingchamber, means for forcing oil from the pipe still into the crackingchamber, an evaporator connected with thecracking chamber, a condenserconnected with the evaporator, means to conduct condensate to the pipestill, a conductor for leading oil from the evaporator back to thecracking chamber, and a condenser connected with the cracking chamber.

CARBON P. DUBBS.

